External combustion engine

Abstract

An external combustion engine includes: a main container sealed with a working fluid in a liquid state adapted to flow; a heater for heating a portion of the working fluid in the main container and generating the vapor of the working fluid; a cooler for cooling and liquefying the vapor; an output unit for outputting by converting the displacement of the liquid portion of the working fluid generated by the volume change of the working fluid due to the generation and liquefaction of the vapor into mechanical energy; and an auxiliary container communicating with the main container. The heater, the cooler and the output unit are arranged in order, in the direction of displacement of the working fluid. The working fluid is sealed in the auxiliary container which communicates with the portion of the main container nearer the output unit than the cooler. The engine further includes a communication area adjusting unit for establishing communication between the main container and the auxiliary container with a first communication area in normal operation mode and with a second communication area larger than the first communication area at the time of engine start. Thus, a predetermined output is produced quickly after engine start.

1. An external combustion engine comprising:
 a main container containing a working fluid adapted to flow in liquid state; 
 a heater for heating part of the working fluid in the main container and generating vapor of the working fluid; 
 a cooler for cooling and liquefying the vapor; 
 an output unit for outputting by converting the displacement of the liquid portion of the working fluid generated by the volume change of the working fluid due to the generation and liquefaction of the vapor into mechanical energy; and 
 an auxiliary container communicating with the main container; 
 wherein the heater, the cooler and the output unit are arranged in that order in the direction of displacement of the working fluid; 
 wherein the auxiliary container containing the working fluid; 
 wherein the auxiliary container communicates with the portion of the main container nearer the output unit than the cooler; 
 the external combustion engine further comprising a communication area adjusting means for establishing communication between the main container and the auxiliary container through a first communication area in normal operation mode and establishing communication between the main container and the auxiliary container through a second communication area larger than the first communication area in engine starting mode. 
 
     
     
       2. The external combustion engine according to  claim 1 ,
 wherein the communication area adjusting means includes a choke for establishing communication between the main container and the auxiliary container in normal operation mode, and a path larger in flow path area than the choke for establishing communication between the main container and the auxiliary container in starting mode. 
 
     
     
       3. The external combustion engine according to  claim 2 ,
 wherein the path has a check valve for allowing the working fluid to flow from the main container to the auxiliary container and blocking the reverse flow of the working fluid from the auxiliary container to the main container. 
 
     
     
       4. The external combustion engine according to  claim 3 ,
 wherein the check valve is a spring-type check valve including a spring portion having the spring constant adapted to change with temperature, and the working pressure of the check valve changes with the spring constant, and 
 wherein the spring portion is heated by a heating means controlled by a control means reducing the working pressure in starting mode below the working pressure in normal operation mode. 
 
     
     
       5. The external combustion engine according to  claim 2 ,
 wherein the communication area adjusting means includes a valve for opening/closing the path and a control means for controlling the operation of the valve so as to be in a closed state in normal operation mode and to be in an open state in starting mode. 
 
     
     
       6. The external combustion engine according to  claim 1 ,
 wherein the communication area adjusting means includes a variable choke mechanism for establishing communication between the main container and the auxiliary container, and a control means for controlling the variable choke mechanism in such a manner as to increase the opening degree of the variable choke mechanism in starting mode beyond the opening degree of the variable choke mechanism in normal operation mode. 
 
     
     
       7. The external combustion engine according to  claim 1 ,
 wherein the main container includes a first container, a second container having the same configuration as the first container and only one auxiliary container communicating with both the first container and the second container. 
 
     
     
       8. The external combustion engine according to  claim 1 ,
 wherein the output unit includes a casing containing the working fluid, and the casing makes up the auxiliary container. 
 
     
     
       9. The external combustion engine according to  claim 2 ,
 wherein the output unit includes a casing containing the working fluid, a cylinder for establishing communication between the casing and the main container and a piston supported slidably in the cylinder and driven by the displacement of the working fluid, 
 wherein the casing makes up the auxiliary container, and 
 wherein a minuscule clearance existing between the piston and the cylinder makes up the choke.